Harold and Chester, a dog and a cat, are boarded at Chateau Bow-Wow where Chester becomes increasingly alarmed by the strange behavior of his fellow guests.

Long Synopsis:

Harold and Chester could hardly believe it. The Monroe family was going on vacation without them. Bunnicula, the family rabbit, would be boarded with a neighbor. But they, the family's loyal dog and cat, were to be sent away with strangers; they were to spend a week at Chateau Bow-Wow.

Chateau Bow-Wow, observed Chester, soon after they arrived, could more properly be called Howliday Inn. Though what was howling, neither of them knew. Chester had his suspicions however; only a werewolf could make that chilling sound.